1. Field of the Invention
The invention generally relates to an optical apparatus and a method for identifying an object, in particular, to an optical apparatus for fingerprint application and a method for identifying a fingerprint.
2. Description of Related Art
Optical devices such as optical fingerprint collection devices are widely used for fingerprint collection and identification. The collection of fingerprints through optical devices is based on optical imaging the finger surface through optical sensors. Most conventional optical devices for fingerprint collection, such as a reflection type fingerprint reader, use a prism which is directly contacted by a finger of the user, and a light source and an image capture unit is installed at different side of the prism. Through total internal reflection and frustrated total internal reflection (FTIR), the ridge-valley patterns of a fingerprint may produce a high contrast fingerprint image. On the other hand, some optical devices for fingerprint collection use a transmission type fingerprint reader to collect the fingerprint. Light signals transmit into the finger and then scatter back to the image capture unit. In certain related arts, the light signals may go through the whole finger.
For information security, how to manufacture an optical device for fingerprint collection that has anti-spoofing capability and satisfactory identification quality is one of the most important topics in the pertinent field.